California is home to some of the busiest highways in the country. With millions of drivers commuting daily, it’s no surprise that the Golden State also leads the nation in serious freeway accidents. From gridlocked Los Angeles interchanges to high-speed Central Valley stretches, these freeways are notorious for collisions. Below are the 10 most dangerous freeways in California for car accidents, based on traffic data, accident reports, and safety studies.

1. I-5 (The Golden State Freeway)

Stretching the entire state, I-5 is one of the most heavily traveled highways in California. The combination of long-haul trucks, high speeds, and congestion in Los Angeles and Sacramento make it a hotspot for serious crashes. According to the California Highway Patrol’s Statewide Integrated Traffic Records System, I-5 consistently ranks among the state’s highest in accident volume. Source: https://iswitrs.chp.ca.gov/Reports/jsp/userLogin.jsp

2. I-405 (San Diego Freeway)

Known as one of the busiest freeways in the United States, the 405 is infamous for its constant congestion in Los Angeles and Orange County. Caltrans reports heavy traffic volumes that contribute to rear-end accidents and multi-vehicle pileups. Source: https://dot.ca.gov/

3. US-101 (Hollywood Freeway/Ventura Freeway)

The 101 cuts through downtown Los Angeles, Hollywood, and up the coast. Heavy tourist traffic, confusing interchanges, and stop-and-go congestion make this freeway one of California’s most accident-prone. A Los Angeles Times report noted that the 101 is among the deadliest freeways in LA County. Source: https://www.latimes.com/

4. I-10 (Santa Monica Freeway)

The I-10 links Los Angeles to Arizona and is a key trucking route. In LA, it’s one of the busiest stretches of roadway in the nation, with high accident rates due to constant merging and lane-changing. Data from the National Highway Traffic Safety Administration (NHTSA) shows that the I-10 has some of the highest fatal crash numbers in California. Source: https://www.nhtsa.gov/research-data/fatality-analysis-reporting-system-fars

5. SR-99 (State Route 99)

Running through the Central Valley, SR-99 is consistently ranked as one of the deadliest highways in the country. A 2016 report by ValuePenguin based on NHTSA data found SR-99 to be the most dangerous highway in the U.S., with the highest fatal accident rate per 100 miles. Source: https://www.valuepenguin.com/

6. I-80

Connecting the Bay Area to Sacramento and Nevada, I-80 sees a mix of heavy commuter traffic and long-haul trucking. Winter weather in the Sierra Nevada adds another layer of danger with icy roads and poor visibility. Caltrans road condition reports often list chain requirements and closures along this route. Source: https://roads.dot.ca.gov/

7. I-15

The I-15 corridor runs from San Diego through the Inland Empire to Las Vegas. High speeds, weekend tourist traffic, and drunk driving incidents make it especially hazardous. According to NHTSA’s Fatality Analysis Reporting System (FARS), the I-15 has one of the highest DUI-related crash rates in California. Source: https://www.nhtsa.gov/research-data/fatality-analysis-reporting-system-fars

8. I-580

In the Bay Area, I-580 connects Oakland, Livermore, and Tracy. The mixture of fast-moving commuter cars and big rigs often leads to serious collisions, especially in the Altamont Pass area. Local media frequently report on severe crashes here. Source: https://www.mercurynews.com/

9. SR-1 (Pacific Coast Highway)

While scenic, the Pacific Coast Highway is also dangerous. Narrow lanes, sharp curves, and distracted drivers stopping for ocean views make this highway a frequent site of severe accidents. Travel advisories warn drivers of hazardous stretches along Big Sur and Malibu. Source: https://www.visitcalifornia.com/

10. I-210 (Foothill Freeway)

Stretching across the San Gabriel Valley, the 210 carries heavy commuter traffic. Sudden lane shifts and high speeds increase the risk of multi-vehicle accidents. CHP traffic incident pages regularly show collisions along this corridor. Source: https://cad.chp.ca.gov/

What to Do If You’re Injured on a California Freeway

If you or a loved one has been involved in a freeway accident, knowing what to do next is critical:

• Seek medical attention immediately.
• Document the scene with photos or videos.
• Gather witness contact information.
• Report the accident to law enforcement.
• Contact an experienced California car accident lawyer.

At Hillstone Law, our attorneys have helped countless accident victims recover compensation for medical bills, lost wages, and pain and suffering. We know the local freeways and we know how to fight the insurance companies.

Free Consultation

If you’ve been hurt in a freeway accident, call Hillstone Law today for a free consultation. We’ll review your case and help you understand your rights.